Process of producing titanium compounds.



UNITED STATES PATENT OFFICE.

HOWARD SPENCE, MANCHESTER, ENGLAND.

PROCESS or Puooucme TITANIUM COMPOUNDS.

'srnoxrloauron' forming as of Letters Patent No. 681,993, dated September 3, 1901.

Original application filed June 3, 1899, Serial No. 719,299. Dividad and this application filed December 28,1899. Serial No. 741,489- (No specimens.)

To all whom it may concern;

Be it known that I, HOWARD SPnNon, a subject of the Queen of Great Britain and Ireland, residing at Manchester, in the county of Lancaster, England, have invented Improvements in Processes of Producing Titanium Compounds, of which the following is a specification.

Hitherto no soluble compound of titanium has been produced on a large scale as an article of commerce and the laboratory processes which have been described are not suitable for the production of such compounds except at a price which would be, practically speaking, prohibitive.

Now this invention relates to the production of soluble compounds of titanium having the general formula TiO ,2(S ),X 0 where X represents either sodium, potassium, or ammonium, (NH,,.) From these soluble and industrially useful compounds of titanium (respectively, a crystalline compound of titanic acid, sulfuric acid, and soda, a crystalline compound of titanic acid,sulf uric acid, and potash, and a crystalline compound of titanic acid, sulfuric acid, and ammonia) various other useful compounds of titanium may also be produced. It should be noted that the potash salt difiers from the well known compound of titanic 'acid,sulfuric acid, and potash mentioned in the text-books, the formula of the latter being TiO ,3 S0 ,K 'O, while that of the former is TiO ,2 SO, ,K O.

In carrying out this invention the titanic acid may be obtained from-any suitable material containing titanic acid, provided that it exists therein in a form readily soluble in sulfuric acid or that it has been so rendered soluble by a preliminarytreatment, such as by fritting or fusing with carbonate of soda, as is described in my application, Serial N0.

= 719,299, filed June 3, 1899, of which this apable method, depending upon the particularsubstance being treated. The said material is then digested in heated sulfuric acid, (either in the open or under pressure,) the quantity of sulfuric acid employed being in excess of what is actually required for the solution of the titanic acid. The strength of the sulfuric of the particular alkali to be employed-- i. 12., either sulfate-of soda-,sulfate of potash,

or sulfate of ammoniaepreferably in the form of neutral or normal sulfate, such as neutral sodium sulfate, (Na,SO the quantity added being suflicient to-potent-ially form some or all of the free or uncombined sulfuric acid present into .an acid sulfate or bisulfate of the alkali. Thus forevery molecule of titanic acid in solution there is added at least one molecule of alkali sulfate.

If, for example, the solution contains about twenty percent. of free sulfuric acid and about sixteen per cent. of titantie acid, then for every one hundred parts, by weight,.of the solution we may add about fifty parts, by weight, of sodium sulfate when producing the sodium titanium double sulfate. At this stage, as also in the case of the solution produced byattacking the material with the acid sulfate, as described in my other application aforesaid, the solution is concentrated by evaporation-i. e., by boiling the solution in the ordinary way until it has acquired a specific gravity of about 1.4, the temperature at this stage being about 110 centigrade, whereby a separation is eifected of the crystalline compound of titanic acid, sulfuric acid, and the alkali employed. The crystalline compounds separate out mainly during concentration of the solution obtained.

by the above-described methods, If the solution contains impurities in such proportion as to be detrimental, the crystalline crop of the compound may be removed by well known means from the liquor while the latter is hot. If, however, the solution is comparatively pure, it may be allowed to cool in order to obtain as large a yield as possible of the compound. It is to be noted that the presence of a considerable proportion of alumina in the material containing titanic acid is object-ionable,as it interferes largely with the separation of the crystalline compound. If present in large proportion, it would very greatly reduce the quantity obtainable. The product thus obtained may be further purified, if necessary, by dissolving it in dilute sulfuric acid of about 1.2 specific gravity, concentrating the solution so obtained as before, and again crystallizing out the compound. It is found that this result is greatly assisted by the addition of sufiicient neutral or normal sulfate of the alkali employed, to convert potentially into an acid sulfate some or all of the sulfuric acid that has been added in the form of dilute acid, as abovedescribed. The addition of sufficient neutral sulfate of the alkali to potentially form about two-thirds of the sulfuric acid so added into an acid sulfate or bisulfate (NaHSO, or KHSO or NH HSO is a proportion found to give a good result.

The following is an example of the process according to this invention: Eighty grams of finely-powdered native rutile were intimately mixed with one hundred and seven grams of soda-ash (fifty-eight per cent. alkali) and placed in a muflle,which was gradually heated to a dull-red heat during the first hour. heat was ,then gradually increased till a bright red was attained, the frit being frequently stirred to prevent baking together. This heat, which was the limit attained without fusion of themass, was maintained for about three hours. The mass was then allowed to cool, crushed, and lixiviated in four hundred cubic centimeters of hot water in order to remove as much of the soda as possible, and was separated from the liquor on a vacuum-filter, on which the residue was further washed. On removal from the filter the mass weighed one hundred and eight grains. It was then treated with two hundred and forty grams of strong sulfuric acid (1.86 specific gravity) that'had been previously mixed with one hundred cubic centimeters of water and the whole heated in a glass vessel over a flame for a fewminutes, then another one hundred cubic centimeters of warm water were added gradually to the solution and the heating continued for a further five minutes. The solution was then filtered from the insoluble silica and other matter on an asbestos cloth and the insoluble matter washed with one hundred cubic centimetersof cold water,.this liquor being added to the main filtrate. To the clear Thefiltrate thus obtained two hundred and ninety grams of N21 SO .1OH O were added and the liquor brought to the boil. In this case,.the liquors having been kept strong, a rich crop of the compound separated out without further evaporation being previously necessary and the crop was thoroughly washed with a large quantity of cold water (about five hundred cubic centimeters) on a filter-pump. As the crystals, especially when formed on a small scale, are very small and retain impurities readily, a large quantity of water for washing should be used.

The soluble crystalline compound of titanic duction of new soluble compounds of titanic acid, sulfuric acid and alkali having as set forth the formula TiO 2(SO )X O from a titanic-acid-containing substance in which the titanic acid is readily soluble in sulfuric acid, which consists in digesting the titanicacid-containing substance in heated sulfuric acid in slight excess and maintaining in the" liquor an excess of sulfuric acid to the lim= ited extent necessary to retain the titanic acid in solution, adding to the clear solution of the titanic acid in sulfuric acid, sulfate of the particular alkali employed in the proportion of not less than one molecule of alkali sulfate for every molecule of titanic sulfate contained in solution, and crystallizing out the resulting compound of titanic "acid, sulfuric acid and alkali by evaporating the said clear solution to a specific gravity of about 1.4.

2. The herein-described process for the production of new soluble compounds of titanic acid, sulfuric acid and alkali having as set forth the formula TiO 2(SO )X O which consists in dissolving titanic acid in heated dilute sulfuricacid, such sulfuric acid being in excess of what is actuallyrequired for the solution of the titanic acid, adding an alkaline sulfate to the resulting solution, crystallizing out the resulting compound of titanic acid, sulfuric acid and alkali, dissolving the crystallized compound in dilute sulfuric acid adding normal sulfate of the alkali employed to the resulting solution, and again crystallizing out the compound of titanic acid, sulfuric acid, sulfurieaoid and alkali, dissolglng the "681,993 I I f 3 sulfuric acid such dilute sulfuric-acid being lizing out the compound of tit'anie acid, sul-i .xo f in excess of what is actually required for the furic acid and alkali 'solution of the titanic acid, adding an alka- Signed at Manchester, county of Lancaster, line sulfate to the resulting solution, crys- England, this 1st day of December, 1899.

tallizing out the resulting compound of titaiii-c HOWARD SPENCE crystallized compound in dilute sulfui'ie acid, Witnesses adding normal sulfate of the alkali employed FRED BERRY,

to the resulting solution, and figain crystal- ARTHUR WILDING; 

